Apparatus for continuously processing strips



Sept. 7, 1948. F. K. scHEFE APPARATUS FOR CONTINUOUSLY PROCESSING STRIPSFiled Jan. so, 1945 3 Sheets-Sheet 1 mvx-:Nron .Frederic/f K. Sc/lzfArron Sept. 7, 19.48. F. K. scHEl-'E APPARATUS' FOR CONTINUOUSLYPROCESSINGl STRIPS Filed Jan. so, 1945 y 3 Sheets-Sheet 2 h. h. W/////.///f///.////////////rk\\ fregar/2 Arrmnus Foa coNTINuoUsLYPROCESSING STRIPS Filed Jan. 30, 1945 F. K. SCHEFE Sept. 7, 1948.

5 Sheets-Sheet 5 INVENTOR. Frede/ick K. Sche/'e BY-v ATTOR/VE Y PatentedSept. 7, 1948 APPARATUS Foa coN'rINUoUsLY raocnssmc. srarrs Frederick K.Schefe; Gary, Ind., asslgnor to Carnegie-Illinois SteeLCorpox-ation, acorporation of NewJersey Application January 30, 1945,' Serial No.575,292

3 Claims. 1 This invention relates to a method and apparatus forcontinuously processing strip and especially for continuously annealingor heat treating strip in a vertical furnace.` Continuous metallic stripis commonly heat treated in a horizontal furnace, but such furnacesoccupy considerable floor space and have other objections. For example,the usual practice is to provide long horizontal heating and coolingzones for the strip which is supported on and fed by revolving rolls. Insuch apparatus the strip sags between the rolls and is subjected totension and stretching while hot. To avoid difliculties inherent inhorizontal heat treating, equipment has been designed in which the stripmaterial is positioned vertically during heating and cooling, Most ofthese arrangements include tensioning the strip by mechanical means inorder to move the strip in the desired path of travel and, since thestrip is heated while under tension, it will stretch in the same manneras when annealing in a vertical furnace. The present trend is to heattreat the strip at as high a speed as possible and this aggravates thestretching of the strip under tension. v

It is an object of my invention to provide heat treating apparatus inwhich the strip is heated while untensioned.

Another obiect is to heat the strip while un supported.

These and other objects will be more apparent after referring to thefollowing specification and attached drawings, in which: l

Figure 1 is a schematic view showing one embodiment of my invention;

Figure 2 is a fragmentary schematic view of a second embodiment of theinvention: and

Figure 3 is a schematic wiring diagram showing the operation of devices31 and 36.

Referring more particularly to the drawings, the reference numeral 2indicates an uncoiler for supporting a coil of strip S to be treated. Asecond uncoiler 4 is located adjacent to and between the first uncoilerand the furnace in line with the strip as it is fed from the firstuncoiler 2. Pinch rolls 6 feed the forward end of the strip from a newcoil to the shears 8 and welder I0, the shears being used to trim theends of the coils of strip before they are welded together by means ofthe Welder I0. The strip S passes from the Welder I through the pinchrolls I2 and then is pulled upwardly by means of a pair of power drivenrolls I4. A second pair of rolls I6 is provided at the same level asrolls I4 anda loop D is formed between the two pairs of rolls. A secondloop E 2 is formed in the strip between the rolls I6 and a water cooledroll I8. As the strip passes upwardly in the second loop, it passesthrough a preheating furnace 20 where it is heated from room temperatureto a temperature of approximately 800 to 1000 F. From the roll I3 thestrip passes downwardly through a heating furnace 22 and a third loop Fis formed between roll I8 and pulling rolls 24. As the strip leaves thefurnace 22, at a temperature of from 1100 to 1350 F., it

passes between guide rolls 26 to a. cooling chamber 28 where the stripis cooled to a temperature of between 250 and 900 F. The rolls 26 aredriven at strip speed and are spaced apart a greater distance than thethickness of the strip so that they do not contact it intimately.However, the distance between the rolls is less than the width of theexit portion of the furnace 22 so that the rolls prevent scratching ofthe strip surface by contact with the exit portion of the heatingfurnace 22 or the sides of the cooling chamber 28, A fourth loop ofstrip G is formed between the rolls 24 and pinch rolls 30 and a. fifthloop H is formed between the rolls 30 and tension rolls 32. Side guides33 are provided for the strip prior to its entry into the rolls 2A andsimilar guides 34 are provided on the entry side of rolls 32 to keep thestrip in the desired lateral path. From the tension rolls 32 the strippasses through the shears 35 to the coller 36. Conventionalphotoelectric tube arrangements or similar devices 31 are provided formaintaining loop D in full line position and similar devices 38 maintainloop G in elevated position. The remaining loops are also maintained inposition by phctoelectric cells 39 in a well known manner, which doesnot constitute part of the present invention.

The operation of the devices 31 and 38 is shown in Figure 3. To controlloop D there is an upper light source 50 and a lower light source 52 atone side of the loop and an upper photoelectric cell 64 and a bottomphotoelectric cell 56 at the opposite side of the loop, theseconstituting the photoelectric tube arrangement 31 f or loop D.Photoelectric cell 54-is connected through a suitable amplifier 58, suchas Westinghouse Electrics "Photo-Troller, to a relay which is soarranged thatl it closes its contacts when light to th'e photoelectriccell 54 is unobstructed by loop D. Photcelectric cell 56 is connected inlike manner through an amplifier 62 to a relay 64 which is so arrangedthat its contacts will close when light is obstructed by loop D. Wheneither relay or 64 is closed, a circuit from a power source 66 iscompleted to one of the reversely wound series field windings 88 and 10,of motor 12 which controls the position of the arm of rheostat 14.Rheostat 14 is connected in the circuit of field winding 18 of the motor18 which drives roll I4. The armature of motor 18 is energized frompower source 68 through the switch 80.

It will be seen that as longi as the strip is being fed into the loop Dat the same speed as, that at which it is being withdrawn, the length ofthe loop will not change and the. resistance of rheostat 14 will remainconstant. If the loop becomes too short, the photo-electric cell 54 willbe exposed to its light source 50, causing energization of relay 80,which closes the circuit to motor 12 through field winding 68 androtates the motor 12 in a direction which will shift the rheostat arm toweaken the field produced by winding 16 of motor 18. This increases thespeed oi.' motor 18 and causes the loop to resume its normal position.Conversely, if the loop becomes too long, the lower photoelectric cell56 will be shadowed by the loop D and relay 64 will be energized tocomplete the circuit to motor 12 through field winding 10, causing themotor to run in the opposite direction. This changes the resistance ofrheostat 14 so that the field produced by winding 16 is strengthened,whereby motor 18 runs at a decreased speed and the loop is shorteneduntil it resumes its normal position. When renewing coils, switch 80 isopened, this stopping rotation of motor 18 and roll I4, whereupon loop Drises completely out of the control zone of photoelec- .tric device 31.After the new coil is in operating position, switch 80 is closed,starting motor 18 and rolls I4 at the increased speed demanded byphotoelectric cell 54. This increased speed continues until loop Dreturns to its normal position.

The photoelectric tube arrangement 38 consists of a top light source 82anda bottom light source 84 located on one side of loop G andphotoelectric cells 86 and 88 located on the opposite side.Photoelectric cell 86 is connected through an amplifier 90 to a relay 92which is so connected that its contacts are closed when light isunobstructed by loop G. Photcelectric cell 88 is connected in likemanner through an amplifier 94 to a. relay 96 whichis so connected thatits contacts are closed when light is obstructed by G. Closing thecontacts of either relay 92 or 96 completes a circuit to one of thereversely wound ing |00, causing the motor to rotate in a direction toshift the rheostat arms so as to strengthen the fields ||4, ||8 and |22of their related motors, thus decreasing their respective speeds. Ifloop G becomes too long the lower photoelectric cell 88 will be'shadowedand relay 98 will be energized closing the circuit to motor |02 throughfield winding 98, thus causing the motor to rotate in a direction toshift the rheostat arms so as to weaken fields ||4, I|8l and |22 ottheir related motors, thus increasing their respective speeds until loopG resumes its normal position. When it is desired to change coils,switch H2 is opened which stops motors I|0, ||6 and |20, whereupon theloop G lengthens and drops completely out of the control zone ofphotoelectric device 38. After the processed coil is removed and a newcoil started on the recoiler 36, switch |I2 is closed to start motorsI|0, II6 and |20 at the increased speed demanded by the photoelectriccell 88. This continues until loop G assumes its normal position.

The operation of the device is as follows:

With the processing line operating normally, the various loops are inthe positions shown in full lines in Figure 1. At this, time powerdriven rolls I4, I6, I8, 24, 26 and 30 are being driven at strip speed.`The uncoiler 2 is providing lust enough back tension to control thestrip movement and the tension rolls 32 are providing sumcient pulltension for efficient recoiling of the treated strip by the coller 36.It will be seen that the rapidly moving and heated strip in loops E andF is not subjected to any applied tension and the only tension existingin the strip is that due to the weight of the strip in the loops. Whenseries fields 98 or |00 of motor |02 which controis the position of thearms of rheostats |04, |06 and |08. Motor I|0 which drives roll 30 hasits armature circuit energized from power source,

66 through a switch I I2 and its iield winding ||4 connected to voltagesource 66 through rheostat |04. `Motor I I6, which drives the tensionrolls 32, has its armature energized from power source 66 through switchI I2 and its field winding II8 connected to power source 66 through therheostat |06. Motor |20 which drives the recoiler 36 has its armaturecircuit energized from power source 66 through switch I2 and its fieldwinding |22 connected to power source 66 through rheostat |08.

It will be seen that as long as the strip is Withdrawn from the loop Gat the same rate of speed as it is being fed, the length of the loopwill not change. Should loop G become too short as happens when theWithdrawal speed is too fast, the photoelectrical cell 86 will beexposed to its light source 82,` causing energization of relay 82, whichcloses the circuit to motor |02 through field windpositioning a new coilof strip the uncoiler 2 and rolls I4 are stopped and that part of theequipment located in the line after the rolls I4 continue to operate atline speed, the strip stored in loop D supplying the necessary materialuntil a new coil is positioned and fastened to the end of the precedingstrip. Prior to exhausting the strip on uncoiler '2, a second coil ofstrip is mounted on uncoiler 4 and after the rolls I4 are stopped andthe trailing end of the first strip squared by shears 8,V the strip isentered from uncoiler 4 through pinch rolls 6 to the shears 8 whichsquare the leading end of the strip. The ends of the coils of strip arethen welded together by the Welder |'0. This trimming and weldingoperation is that which is commonly used to weld strips end to end invarious processing operations and as such does not constitute part of myinvention. After the ends are welded together, the rolls I4 are startedand rotated faster than the other rolls in order to restoreloop D to itsoriginal position as controlled by the electrical devices 31, afterwhich uncoiler 4 and rolls I4 will automatically. assume synchronizationand speed relationship with the remaining rotating units of the line. Itwill be understood that the speed of rolls I4 and the length of loop Dcould becontrolled manually, but it is not desired to do so since suchmanual operation requires constant attention.

When removing a treated coil from coller 36,

During 38, rolls 39 and 32 and coller 38 are started in operation at aspeed faster than line speed until loop G again resumes the positionshown in full lines in Figure 1. When the loop G reaches normalposition, all rotating units of the discharge end of the processing linewill automaticallybe returned to operating speed by the electriccontrols I8. If desired, the stopping, starting and speed control ofrolls 30 and 32 and coller 38 may be done manually. In some instances itmay be necessary to provide a second coller adjacent coiler 38 in orderthat the strip S may be ready for coiling by the time loop G reaches thedotted line position.

Figure 2 shows a second embodiment of the invention in which the feedend of the line to rolls Il and the discharge end of the line afterrolls 39 are the same as in Figure l. However, only three loops of stripK, L and M are formed between rolls I4 and 30. The loop K is formedbetween rolls I4 and roll 40; loop L is formed between roll 40 and rolls4|; and loop M is formed between rolls 30 and Il. The strip in loop Lpasses downwardly through a preheating furnace 42 where it is heated toa temperature of from 800 to 1000" F. and into a heating furnace 44where itis heated to a temperature of from 1100 to l350 F. From there itpasses upwardly through a cooling chamber 48, which it leaves at atemperature of from 250 to 900 F. The operation of this embodiment isthe same as described above for Figure 1, the rolls il, 30, 40 and 4inormally operating at line speed. When fastening coils together therolls I4 are stopped and' the coils of strip fastened end to end asdescribed above, the strip in loop K supplying the necessary material tokeep the strip moving through the furnace. The rolls Il and otherrotating equipment in the line between the coiler and the rolls il arethen rotated at a speed greater than line speed until the loop K returnsto its normal full line position as controlled by the electrical devices31. In removing a coil of strip from the coller 38, the rolls I0 and 32,and coiler 38 are stopped in the same manner as described above and thestrip is cut in two by the shears 35, the coil removed, and the stripfastened to the mandrel of the coller. I'he rolls 30, 32 and coils I8are then started in operation at a speed greater than line speed untilthe loop M returns to its normal position shown in full lines in Figure2. When loop M reaches its normal elevated position all units in thedischarge end of the processing line will be automatically returned tothe operating speed by the functioning oi the group of electric controlsshown at 38.

While two embodiments of my invention have been shown and described,that other adaptations and modiilcations may be made without departingfrom the scope of the following claims.

I claim:

it will be apparent 1. Apparatus for continuously processing strip whichcomprises means for forming two freely hanging loops of strip, means forpreheating said strip as it passes upwardly in the rst loop, means forheating said strip as it passes downwardly in the second loop, and meansfor cooling said strip as it passes upwardly in the second loop.

2. Apparatus for continuously processing strip which comprises means forfastening coils of strip end to end, means for forming two freely hanging loops of strip, means for preheating said strip as it passesupwardly in the ilrst loop, means for heating said strip as it passesdownwardly in the second loop, means for cooling said strip as it passesupwardly in the second loop, yancl means between the fastening means andthe ilrst loop for storing suiiicient strip to enable the strip tocontinue moving through the heating means while fastening the coilstogether.

3. Apparatus for continuously processing strip which comprises means forfastening coils of strip end to end, means for forming two freelyhanging loops of strip, means for preheating said strip as it passesupwardly-in the rstloop, means for heating said strip as it passesdownwardly in the second loop, means for cooling said strip as it passesupwardly in the second loop, means between the fastening means and therst loop for storing suiilcient strip to enable the strip to continuemoving through the heating means while fastening the coils together, acoiler at the end of the processing line, means for cutting said striplocated in front of the coller, and means between the second loop andcutting means for storing suflicient strip to enable the strip tocontinue moving through the heating means while removing a coil from thecoller.

FREDERICK K. SCHEFE.

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